JP5419911B2 - Ball screw device - Google Patents

Description

  The present invention provides a screw shaft having a spiral screw groove formed on the outer periphery, and guides a large number of balls so that the screw shaft is rotatably accommodated in a part of the screw groove and is circulated in the circumferential direction of the screw shaft. A ball screw device including a ball guide groove formed with a ball guide groove to be moved. The ball guide groove can be easily formed as a ball circulation groove, and the ball guide and the screw shaft can be easily screwed together. The present invention relates to a ball screw device that can be performed properly, and that the compatibility of a ball with a ball guide groove can be facilitated, and that cost reduction and versatility can be improved.

  2. Description of the Related Art Conventionally, a ball screw device as a linear motion device including a ball screw is generally accommodated so as to be able to roll on a screw shaft having a spiral ball transfer groove formed on the outer periphery and a part of the ball transfer groove. And a nut formed with a ball groove for guiding and moving a large number of balls so as to circulate and move in the circumferential direction of the screw shaft.

  However, this type of ball screw device has various configurations for connecting both ends of a ball groove formed on a nut for guiding and moving the ball to circulate a plurality of balls moving in the ball groove. A ball circulation path has been proposed and put into practical use.

  In general, a ball circulation path as a ball groove in a ball screw device is provided on the nut side, and it is proposed to use pieces having various shapes and configurations to make the circulation path member particularly simple. (See Patent Document 1).

  In addition, the ball circulation path is provided on the screw shaft side, the screw shaft is configured to be hollow, a ring member is press-fitted and fitted on the inner peripheral surface, and a mating part mounting portion is provided at one end of the screw shaft. And a ball pick-up guide as ball guide means for guiding the ball to the circulation hole at the positions of the circulation holes provided at both ends of the ball groove of the screw shaft. A ball screw device has been proposed which has a configuration in which a circulation path is provided for connecting the two circulation holes by a half circumference on the outer peripheral surface of the ring member (see Patent Document 2).

  Furthermore, a screw shaft having a helical thread groove formed on the outer peripheral surface, a nut externally fitted to the screw shaft and having a helical thread groove formed on the inner peripheral surface, and the corresponding both screw grooves are formed. A ball screw assembly apparatus including a plurality of balls accommodated in a rolling path, the ball guide having a ball supply hole for supplying the ball to a screw groove of the nut, and being inserted into the nut And a ball screw assembling apparatus comprising a nut pedestal formed with a substantially D-shaped concave portion fitted to a substantially D-shaped convex portion provided on one side surface of the nut. (See Patent Document 3).

JP 2000-120826 A JP 2004-225770 A JP 2008-296324 A

  In the ball screw proposed in Patent Document 1 described above, a closed loop is used to connect both ends of a ball groove formed on a nut for guiding and moving the ball and to circulate a plurality of balls moving through the ball groove. A ball guide having a channel for forming an activation is provided, and when the ball groove is formed in the nut, an expensive dedicated machine is used to appropriately engage with the spiral groove formed on the screw shaft. Thus, precise processing is required so that a large number of balls dimensioned in this way can be effectively stored and arranged. For this reason, it is difficult to facilitate the assembly process of this type of ball screw and to reduce its manufacturing cost.

  In addition, the ball screw device proposed in Patent Document 2 described above is configured separately from the screw shaft in which the ball rolling groove is formed and the circulation path member in which the ball circulation path is formed. It is said that a ball screw device that is easy to process and assemble can be obtained. However, even in this type of ball screw device, in the same manner as the ball screw processing described above, when forming the ball groove in the nut, an expensive dedicated machine is used to form the ball groove and precise processing is required. At the same time, the assembly work becomes complicated, and it is still difficult to reduce the manufacturing cost.

  Furthermore, in the ball screw device proposed in Patent Document 3 described above, the ball guide has a ball supply hole for supplying the ball to the screw groove of the nut, and a ball guide inserted into the nut, and one side surface of the nut By providing a nut pedestal formed with a substantially D-shaped recess that is fitted to a substantially D-shaped protrusion provided on the ball, the nut can be accurately aligned with the nut pedestal, and the ball A person who can assemble a ball screw capable of improving the durability of the screw. However, even in this type of ball screw, as in the ball screw processing described above, the ball groove forming process in the nut requires precise processing using an expensive dedicated machine. In addition to facilitating the assembly work, it is also difficult to reduce manufacturing costs.

Therefore, the present inventor has conducted extensive research and trial production to solve the problems of the conventional ball screw device described above, and as a result, a screw shaft having a helical thread groove formed on the outer peripheral surface, and the screw shaft is inserted. A ball guide formed with a ball guide groove corresponding to the screw shaft so as to be partially screwed, and accommodated in the ball guide groove so as to be rollable and partially with respect to the screw groove of the screw shaft. And a plurality of balls accommodated therein, wherein the ball guide is a pair of balls which are joined to each other and formed with a joining surface inclined at an angle corresponding to a lead angle of the screw shaft with respect to a vertical surface of the screw shaft in the axial direction. A ball guide groove comprising a guide piece, and a ball guide groove that enables circulation of a plurality of balls partially accommodated with respect to the screw groove of the screw shaft at a joint surface of the pair of ball guide pieces; And (1) a ball guide groove that is symmetrically engraved on the joint surface of the pair of ball guide pieces of the ball guide member. (2) The one ball guide piece and the other ball guide are provided symmetrically with respect to the center line connecting the position of the maximum thickness and the position of the minimum thickness on the inclined joint surface of the ball guide piece. The ball guide groove formed on the joint surface with the piece is set so that the position where the ball guide piece becomes the maximum thickness and the position where the minimum thickness overlap each other on the center line, and the center line The ball is formed as a ball guide groove portion formed so that the ball is partially accommodated in the screw groove formed in the screw shaft on one end side, and the ball is circulated on the other end side of the center line. (3) A plurality of sets of the ball guide members configured in this way are combined coaxially and adjacent to each other in the axial direction of the screw shaft, and a required ball guide is formed. with the structure housed fixed in the casing, since it becomes easily can be performed, yet simple structure without the need for expensive dedicated machine molding of the ball guide grooves in the ball guide, a ball screw It has been found that the assembly work as a device can be easily achieved without requiring skill and that the manufacturing cost can be reduced.

  Accordingly, an object of the present invention is to provide a screw shaft having a spiral thread groove formed on the outer peripheral surface, and a ball guide groove corresponding to the screw groove on the inner peripheral surface so as to partially engage with the screw shaft. In the ball screw device comprising: a ball guide formed with a plurality of balls disposed in the ball guide groove and partially received with respect to the screw groove of the screw shaft; It is an object of the present invention to provide a ball screw device that can be easily performed, can be easily configured, can be easily assembled, and can reduce manufacturing costs.

In order to achieve the above object, a ball screw device according to a first aspect of the present invention is configured such that a screw shaft having a helical thread groove formed on an outer peripheral surface thereof is inserted into the screw shaft and partially screwed. wherein comprising screw shaft and a ball guide the formation of the corresponding ball guide groove, and a plurality of balls partially housed the ball guide housed disposed rollably in the groove with respect to the screw groove of the screw shaft In addition , the ball guide has a ball guide member composed of a pair of ball guide pieces that are joined to each other to form a joint surface that is inclined at an angle corresponding to the lead angle of the screw shaft with respect to a vertical surface of the screw shaft in the axial direction. Balls formed by symmetrically engraving ball guide grooves that enable circulation of a plurality of balls partially accommodated with respect to the screw grooves of the screw shaft on the joint surfaces of the pair of ball guide pieces. screw In the location,
The ball guide grooves that are symmetrically engraved on the joint surfaces of the pair of ball guide pieces of the ball guide member, respectively, are a maximum thickness position and a minimum thickness position on the inclined joint surfaces of the pair of ball guide pieces. Are provided symmetrically with respect to the center line connecting the
The ball guide groove formed on the joint surface between the one ball guide piece and the other ball guide piece is arranged such that the position where the ball guide piece has the maximum thickness and the position where the minimum thickness overlap each other on the center line. It is set so as to be joined , and is formed as a ball guide groove portion formed so that the ball is partially accommodated in a screw groove formed on the screw shaft on one end side of the center line. Formed as a ball guide groove portion consisting of a circulation path for circulating the ball on the end side ,
A plurality of sets of the ball guide members configured as described above are combined and coaxially and adjacent to each other in the axial direction of the screw shaft , and are housed and fixed in a required ball guide casing.

The ball screw device according to claim 2 of the present invention is a ball guide configured by combining a plurality of sets of ball guide members including the pair of ball guide pieces adjacent to each other in the axial direction of the screw shaft . Each of the ball guide grooves formed on the joint surfaces of the pair of ball guide pieces is displaced at an equal angle of 90 ° in the rotational direction of the screw shaft with reference to the center line on the joint surface of the ball guide pieces. Four or more ball guide members are combined.

The ball screw device according to claim 3 of the present invention is a ball guide configured by combining a plurality of sets of ball guide members including the pair of ball guide pieces adjacent to each other in the axial direction of the screw shaft . Each of the ball guide grooves formed on the joint surfaces of the pair of ball guide pieces is displaced at an equal angle of 120 ° in the rotational direction of the screw shaft with reference to the center line on the joint surface of the ball guide pieces. It is characterized by combining three or more ball guide members.

In a ball screw device according to a fourth aspect of the present invention, the ball guide member comprising the plurality of pairs of ball guide pieces is 90 ° or 120 ° in the rotation direction of the screw shaft at the outer periphery of the ball guide piece, respectively. An insertion hole through which the support rod can be inserted is provided at a position having an equal angle of °.

Ball screw device according to claim 5 of the present invention, the plurality of sets of ball guides members each comprising a pair of ball guides pieces, respectively to exposed bonding surface and proximity to a portion in which the one of the ball guide piece A ball guide groove having a depth approximating the diameter of the ball is formed along the screw shaft insertion hole, and the joint surface of the other ball guide piece corresponding to this ball guide groove and the approximation thereof. A ball guide groove having a slight depth is formed along the screw shaft insertion hole so as to be partially exposed, and the plurality of balls are joined to the joint surface of each ball guide piece and the screw of the ball guide piece. It is characterized by being housed and arranged so as to be able to roll and circulate in the thread groove of the screw shaft inserted through the shaft insertion hole .

According to the ball screw device of the first aspect of the present invention, the screw shaft in which a spiral screw groove is formed on the outer peripheral surface, and the screw groove so as to be partially screwed through the screw shaft. a ball guide the formation of the corresponding ball guide groove, the disposed ball guide groove a ball screw device that includes a plurality of balls partially housed to screw groove of the screw shaft, the ball guide The ball guide grooves that are symmetrically engraved on the joint surfaces of the pair of ball guide pieces of the member are arranged such that the position of the maximum thickness and the position of the minimum thickness on the joint surfaces inclined of the pair of ball guide pieces are mutually with respect to the center line connecting, Borugai with symmetrically providing the ball guide groove to be engraved on the junction surface between the one of the ball guide piece and the other ball guide piece, to each other at the center line Piece is set so as to be joined so as to overlap and a position where the position and the minimum thickness becomes maximum thickness, so that the ball at one end of the center line is partially housed in a screw groove formed on the screw shaft Formed as a ball guide groove part formed on the other end side of the center line and formed as a ball guide groove part consisting of a circulation path for circulating the ball, a plurality of sets of the ball guide members configured in this way, By forming a configuration in which the screw guide shaft is coaxially and adjacently combined and housed and fixed in a required ball guide casing, the ball guide groove in the ball guide can be easily formed, In addition, the assembly work can be easily achieved with a simple configuration, and the manufacturing cost can be reduced.

According to the ball screw device of the second and third aspects of the present invention, the ball guide grooves that are symmetrically engraved on the joint surfaces of the pair of ball guide pieces are inclined by the pair of ball guide pieces. Provided symmetrically with respect to the center line connecting the position of the maximum thickness and the position of the minimum thickness on the joint surface, and the position and minimum thickness of the ball guide pieces on the center line are the maximum thickness. And a ball guide groove portion formed so that the ball is partially accommodated in a screw groove formed on the screw shaft at one end side of the center line. By providing each as a ball guide groove portion comprising a circulation path for circulating the ball on the other end side of the wire, the ball guide groove can be formed easily and easily. It is possible.

According to the ball screw device of the fourth aspect of the present invention, each of the ball guide grooves formed on the joint surfaces of the pair of ball guide pieces, with respect to the center line on the joint surface of the ball guide pieces as a reference, Four or more ball guide members, each of which is displaced at an equal angle of 90 ° in the rotation direction, are combined, or 120 in the rotation direction of the screw shaft with reference to the center line on the joint surface of the ball guide piece. By assembling three or more ball guide members displaced by an equal angle of °, the assembly work of the ball guide can be performed easily and easily.

According to the ball screw device of the first to fourth aspects of the present invention, when the ball guide formed by combining a plurality of sets of ball guide members is housed and fixed in the ball guide casing, the ball guide is provided. By providing an elastic member such as a spring on one side or both side surfaces of the spring to hold it elastically, it is possible to properly hold each ball guide member and to prevent backlash of the screw shaft against the ball guide. It can be suppressed appropriately.

According to the ball screw device of the first to fourth aspects of the present invention, the ball guide member formed of a pair of ball guide pieces is 90 ° in the rotation direction of the screw shaft at the outer periphery of the ball guide piece. Alternatively, when a ball guide is assembled by combining a plurality of sets of ball guide members by providing an insertion hole through which the support rod can be inserted at a position having an equal angle of 120 °, the support rod is inserted into the insertion hole and each ball The guide member can be set at an appropriate position, and the storage and arrangement of the ball in the ball guide groove can be achieved simply and promptly and appropriately.

According to the ball screw device of the fifth aspect of the present invention, in the ball guide member composed of the pair of ball guide pieces, the screw is provided so that the joint surface of the one ball guide piece and the vicinity or a part thereof are exposed to the joint surface. A ball guide groove having a depth approximate to the diameter of the ball is formed along the shaft insertion hole, and the joint surface of the other ball guide piece and the approximation or one of the same are associated with the ball guide groove. An outer peripheral portion of the ball guide casing for storing and fixing the ball guides composed of the plurality of sets of ball guide members by forming a ball guide groove having a slight depth along the screw shaft insertion hole so as to be exposed. On the other hand, when a strong load is applied, the ball held by the ball guide piece of the ball guide member inside is And is held to the set ball guide groove, it is possible to increase the stability of the ball guide member.

It is a principal part sectional side view showing one example of a ball screw device concerning the present invention. It is explanatory drawing which shows the combination state of four sets of ball guide members which comprise the ball screw apparatus in FIG. (A) is a side view showing a joint separation state of a pair of ball guide pieces common to each set of ball guide members in FIG. 2, and (b) is a side view showing a modification thereof. FIG. 3 is an exploded explanatory view of a first ball guide member of the four sets of ball guide members shown in FIG. 2, wherein (a) is a plan view of a joint surface of one of the two ball guide pieces; (A) is a cross-sectional view taken along the line bb in (a), (c) is a plan view of the joint surface of the other divided ball guide piece, and (d) is a cross-sectional view taken along the line dd in (c). It is. FIG. 3 is an exploded explanatory view of a second ball guide member of the four sets of ball guide members shown in FIG. 2, wherein (a) is a plan view of a joint surface of one of the two ball guide pieces; (A) is a cross-sectional view taken along the line bb in (a), (c) is a plan view of the joint surface of the other divided ball guide piece, and (d) is a cross-sectional view taken along the line dd in (c). It is. FIG. 4 is an exploded explanatory view of a third ball guide member of the four sets of ball guide members shown in FIG. 2, wherein (a) is a plan view of a joint surface of one of the two ball guide pieces, and (b). (A) is a cross-sectional view taken along the line bb in (a), (c) is a plan view of the joint surface of the other divided ball guide piece, and (d) is a cross-sectional view taken along the line dd in (c). It is. FIG. 4 is an exploded explanatory view of a fourth ball guide member of the four sets of ball guide members shown in FIG. 2, wherein (a) is a plan view of the joint surface of one of the two ball guide pieces, and (b). (A) is a cross-sectional view taken along the line bb in (a), (c) is a plan view of the joint surface of the other divided ball guide piece, and (d) is a cross-sectional view taken along the line dd in (c). It is. It is side surface sectional drawing of the ball guide piece which shows the modification of the ball guide groove formed with respect to a pair of ball guide piece in the ball guide member which comprises a ball guide.

  Next, embodiments of a ball screw device according to the present invention will be described in detail below with reference to the accompanying drawings.

  1, FIG. 2, FIG. 3 (a) and FIGS. 4 to 7 show an embodiment of a ball screw device according to the present invention, and FIG. 1 is an explanatory view showing a cross section of the main part of the ball screw device. 2 is an exploded explanatory view of the ball guide comprising a plurality of sets of ball guide members shown in FIG. 1, FIG. 3A is a side view of the ball guide member joined and separated in FIG. 2, and FIGS. 2 is an exploded explanatory view showing a configuration of a joint surface of a pair of ball guide pieces constituting each ball guide member in FIG.

  As shown in FIG. 1, the ball screw device in the present embodiment has a screw shaft 40 having a spiral screw groove 42 formed on the outer peripheral surface, and a screw shaft insertion hole 11 through which the screw shaft 40 is inserted. A ball guide 10 formed with a ball guide groove 20 (see FIG. 4) corresponding to the screw groove 42 so as to be partially screwed with the screw shaft 40, and the screw shaft 40 disposed in the ball guide groove 20. And a plurality of balls 30 partially accommodated in the screw groove 42.

  As shown in FIG. 2, the ball guide 10 basically has a joint surface inclined at an angle θ corresponding to a lead angle θ (see FIG. 1) of the screw shaft 40 with respect to a vertical surface of the screw shaft 40 in the axial direction. 12A, 12B (see FIG. 3 (a) and FIG. 4), the first ball guide member 12 comprising a pair of ball guide pieces 13L, 13R constructed to be joined together, similarly constructed A second ball guide member 14 comprising a pair of ball guide pieces 15L, 15R, a third ball guide member 16 comprising a pair of ball guide pieces 17L, 17R constructed in the same way, and a similar construction. And a fourth ball guide member 18 including a pair of ball guide pieces 19L and 19R. In the present invention, basically, the four ball guide members 12, 14, 16, 18 are coaxially combined in the axial direction of the screw shaft 40 to form a ball guide casing comprising a main body 50 and a lid 52. The ball guide 10 can be configured by being housed and fixed therein.

  Therefore, in the ball screw device of the present embodiment, for example, as shown in FIG. 4, a plurality of balls 30 are formed on the joint surfaces 12A and 12B of the pair of ball guide pieces 13L and 13R in the first ball guide member 12. The ball guide grooves 20 are arranged so as to be freely rollable so as to be accommodated in a part of the screw groove 42 of the screw shaft 40 and to circulate in a circle in the joint surfaces 12A and 12B. It consists of a symmetrically engraved configuration. Similarly to the first ball guide member 12, the second ball guide member 14, the third ball guide member 16, and the fourth ball guide member 18 are each a pair of ball guide pieces 15L, Ball guide grooves 20 are symmetrically engraved on the joint surfaces 14A, 14B, 16A, 16B, and 18A, 18B of 15R, 17L, 17R, 19L, and 19R, respectively (FIGS. 5 and 6). (See FIG. 7). Therefore, by configuring the ball guide members 12, 14, 16, and 18 in this manner, the molding process of the ball guide 10 can be performed easily and easily without requiring an expensive dedicated machine as in the prior art. Can be realized at cost.

  Further, in the ball screw device of the present embodiment, as shown in FIG. 4, they are symmetrically engraved on the joint surfaces 12A, 12B of the pair of ball guide pieces 13L, 13R in the first ball guide member 12, respectively. The ball guide groove 20 is bilaterally symmetric with respect to a center line CL that interconnects the position X having the maximum thickness and the position Y having the minimum thickness on the inclined joining surfaces 12A and 12B of the pair of ball guide pieces 13L and 13R. Provided. The same applies to the second ball guide member 14, the third ball guide member 16, and the fourth ball guide member 18 (see FIGS. 5, 6, and 7).

  In this case, one ball guide groove 20 in the first ball guide member 12 has a position X at which the mutual ball guide pieces 13L and 13R have the maximum thickness and a position at the minimum thickness on the center line CL. It sets so that it may join so that Y may overlap (refer FIG. 2). The same applies to the second ball guide member 14, the third ball guide member 16, and the fourth ball guide member 18 (see FIG. 2).

  Further, on one end side of the center line CL, a ball guide groove portion 20a formed so that the ball 30 is partially accommodated in a screw groove 42 formed on the screw shaft 40, and the other end of the center line CL is formed. On the side, each is provided as a ball guide groove portion 20b comprising a circulation path for circulating the ball 30.

The ball screw device according to the present embodiment shown in FIG. 1 is configured by combining five ball guide members 12, 14, 16, 18, and 12 to constitute a ball guide 10. That is, in each of the ball guide members 12, 14, 16, and 18, with respect to the ball guide groove 20 formed on the joint surface of the pair of ball guide pieces, the center line CL on the joint surface of the ball guide piece is used as a reference. The ball guide members 12, 14, 16, and 18 are sequentially arranged adjacent to each other in a state where they are displaced by an equal angle of 90 ° in the rotational direction of the screw shaft 40 (see FIGS. 4 to 7). They are assembled and assembled (see FIGS. 2 and 1) . When the ball guide members 12, 14, 16, and 18 are assembled and assembled in this way, the order is not limited to the illustrated example. For example, the order of the combinations can be arbitrarily set and combined and assembled. Further, when the ball guide members 12, 14, 16, 18 are combined, the ball guide is formed by combining four or more ball guide members on the basis of the combination of the four ball guide members 12, 14, 16, 18. 10 can be assembled.

  As an alternative, in the ball screw device of the present invention, as described above, the ball guide 10 formed by combining a plurality of sets of ball guide members each including a pair of ball guide pieces is a pair of ball guide members. The ball guide groove 20 formed on the joint surface of the ball guide piece is configured to be displaced at an equal angle of 120 ° in the rotation direction of the screw shaft with respect to the center line CL on the joint surface of the ball guide piece, These ball guide members can be assembled by combining three or more, 12, 14, 16, 18 combinations.

  In the ball screw device of the present invention, the ball guide 10 formed by combining the plurality of sets of ball guide members 12, 14, 16, 18 is stored and fixed in the ball guide casings 50, 52. An elastic member 60 such as a spring can be provided on one side surface or both side surfaces of the ball guide 10 so as to be elastically held (see FIG. 1). Therefore, when the ball guide 10 is housed and fixed in the ball guide casings 50 and 52 as described above, the elastic member 60 is provided so that the joining of the ball guide members 12, 14, 16 and 18 can be properly maintained. And backlash of the screw shaft 40 with respect to the ball guide 10 can be appropriately suppressed.

  Furthermore, in the ball screw device of the present invention, the ball guide members 12, 14, 16, 18 comprising a pair of ball guide pieces include the ball guide pieces 13L, 13R, 15L, 15R, 17L, 17R, In the outer peripheral portions of 19L and 19R, a plurality of sets of nut members 12, 14, 16, and 18 are combined at equal angular positions of 90 ° (or 120 °) in the rotational direction of the screw shaft 40 (see FIG. 1). The insertion hole 22 for inserting a support rod (not shown) that can be positioned in this manner can be provided. Therefore, by inserting the support rod appropriately into the insertion hole 22 thus provided, the plurality of sets of ball guide members 12, 14, 16, 18 can be appropriately combined, and the assembly work of the ball guide 10 can be performed easily and easily. It can be done easily.

  In the ball screw device of the present invention, for example, as shown in FIG. 8, in the ball guide member 12 composed of a pair of ball guide pieces 13L and 13R, the joint surface 12A of the one ball guide piece 13L and the vicinity thereof. Ball guide grooves 20a1, 20b1 having a depth approximate to the diameter of the ball are formed along the screw shaft insertion hole 11 so as to be partially exposed. Ball guide grooves 20a2 and 20b2 each having a slight depth are formed along the screw shaft insertion hole 11 so as to be exposed or partially exposed to the joint surface 12B of the other ball guide piece 13R. The other ball guide members 14, 16, 18 are configured in the same manner. With this configuration, when a strong load is applied to the outer peripheral portion (see FIG. 1) of the ball guide casing 50 that houses and fixes the ball guide 10 composed of the plurality of sets of ball guide members, The ball 30 held by the ball guide member of the ball guide member in the above can be held in the ball guide grooves 20a1 and 20b1 set to the depth dimension, so that the stability of the ball guide member can be improved.

  The preferred embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment. For example, for an arbitrary lead angle θ ′ of the screw shaft, a pair of Setting the inclination angle θ ′ of the joint surface in the ball guide piece [see FIG. 3 (b)], other shapes and configurations of the ball guide and ball guide member, depth dimensions and overall shape of the ball guide groove, etc. Many design changes can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Ball guide 11 Screw shaft insertion hole 12 1st ball guide member 12A, 12B Joint surface 13L, 13R Ball guide piece 14 2nd ball guide member 14A, 14B Join surface 15L, 15R Ball guide piece 16 3rd ball guide Member 16A, 16B Joint surface 17L, 17R Ball guide piece 18 Fourth ball guide member 18A, 18B Joint surface 19L, 19R Ball guide piece 20 Ball guide groove 20a Ball guide groove portion 20b capable of accommodating the ball in the screw groove Ball guide groove portion 22 as circulation path Support rod insertion hole 30 Ball 40 Screw shaft 42 Screw groove 50 Ball guide casing body 52 Ball guide casing lid body 60 Elastic member θ Lead angle of screw shaft X Position of maximum thickness Y Minimum Thickness position CL Center line

Claims (5)

A screw shaft having a helical thread groove formed on the outer peripheral surface, a ball guide having a ball guide groove corresponding to the screw shaft so as to be partially screwed by inserting the screw shaft, and the ball guide groove A plurality of balls that are slidably accommodated and partially accommodated in the thread groove of the screw shaft, and the ball guide is a lead of the screw shaft with respect to a vertical surface in the axial direction of the screw shaft. A ball guide member composed of a pair of ball guide pieces that are joined to each other and formed with a joint surface that is inclined at an angle corresponding to the angle, and the joint surface of the pair of ball guide pieces is in relation to the screw groove of the screw shaft. In a ball screw device formed by symmetrically engraving ball guide grooves that enable circulation of a plurality of partially contained balls ,
The ball guide grooves that are symmetrically engraved on the joint surfaces of the pair of ball guide pieces of the ball guide member, respectively, are a maximum thickness position and a minimum thickness position on the inclined joint surfaces of the pair of ball guide pieces. Are provided symmetrically with respect to the center line connecting the
The ball guide groove formed on the joint surface between the one ball guide piece and the other ball guide piece is arranged such that the position where the ball guide piece has the maximum thickness and the position where the minimum thickness overlap each other on the center line. It is set so as to be joined , and is formed as a ball guide groove portion formed so that the ball is partially accommodated in a screw groove formed on the screw shaft on one end side of the center line. Formed as a ball guide groove portion consisting of a circulation path for circulating the ball on the end side ,
A ball characterized in that a plurality of sets of the ball guide members configured as described above are combined and coaxially and adjacent to each other in the axial direction of the screw shaft , and are housed and fixed in a required ball guide casing. Screw device. A ball guide formed by combining a plurality of sets of ball guide members including the pair of ball guide pieces adjacent to each other in the axial direction of the screw shaft is a ball guide formed on the joint surface of the pair of ball guide pieces. 4 or more ball guide members, each of which is displaced at an equal angle of 90 ° in the rotation direction of the screw shaft with respect to the center line on the joint surface of the ball guide piece as a reference, are combined with the groove. The ball screw device according to claim 1 . A ball guide formed by combining a plurality of sets of ball guide members including the pair of ball guide pieces adjacent to each other in the axial direction of the screw shaft is a ball guide formed on the joint surface of the pair of ball guide pieces. For the groove, combining three or more ball guide members, each of which is displaced at an equal angle of 120 ° in the rotational direction of the screw shaft with respect to the center line on the joint surface of the ball guide piece. The ball screw device according to claim 1 . The plurality of sets of ball guide members , each consisting of a pair of ball guide pieces, are inserted through a support rod at positions equal to 90 ° or 120 ° in the rotational direction of the screw shaft on the outer periphery of the ball guide pieces. The ball screw device according to any one of claims 1 to 3, wherein an insertion hole is provided. Wherein the plurality of sets of ball guides members each consisting of a pair of ball guides pieces, respectively along the threaded shaft insertion hole so as to be exposed bonding surface and proximity to a portion in which the one of the ball guide piece, the diameter of the ball A ball guide groove having an approximate depth dimension is formed, and the joint surface of the other ball guide piece corresponding to the ball guide groove and the screw shaft insertion hole so as to be substantially or partially exposed to the joint surface. Forming a ball guide groove having a slight depth dimension , and the inside of the screw shaft thread groove through which the plurality of balls are inserted into the joint surface of each ball guide piece and the screw shaft insertion hole of the ball guide piece, The ball screw device according to any one of claims 1 to 4 , wherein the ball screw device is stored and arranged so as to be rotatable and circulated .

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